import urllib,os
def ss(a,b,c):
    '''
    a yixiazai
    b shujukuai
    c yuanc
    '''
    per=100.0*a*b/c
    if per>100:
        per=100
    print '%.2f%%' % per
url='https://www.python.org/ftp/python/3.5.0/python-3.5.0.exe'
local=os.path.join('/data/softwore','python-3.5.0.exe')
urllib.urlretrieve(url,local,ss)